Umpolung of reactivity at the C-5 position of uracil: 1,2 facile nucleophilic reactions of thiolate ions at C-5 of 6-cyano-1,3-dimethyluracil to procure 5-alkyl or 5-aryl-thio-1,3-dimethyluracils

Abstract

1,3-Dimethyluracil-6-carbonitrile 1 with thiolate ions generated in situ from thioiminium salts or thiols under phase transfer catalytic conditions undergoes umpolung of reactivity at C-5 to give 5-alkyl- or 5-aryl-thio-l,3-dimethyluracils as the major or sole products. However, propane-1,3-dithiol causes reductive decyanation of 1 to 1,3-dimethyluracil.